In retrospect, it may have been the most serious threat to Obama's campaign  clips of fiery sermons delivered by his mentor and former pastor of 20 years, the Rev. Jeremiah Wright. Catnip to cable TV and Rush Limbaugh, Wright was repeatedly shown criticizing America and pushing conspiracy theories about AIDS and drugs in the black community. The videos, repeated endlessly, only fed innuendo that Obama was a sinister figure hiding a radical agenda. With the tempest swirling and his poll numbers starting to slip, Obama confronted the issue head-on in a speech delivered in Philadelphia. In one of the few direct invocations of race by the candidate, he sought to explain Wright's rhetoric by placing him in a broader, complicated context of race relations in America. Though widely praised for its honesty and eloquence, the landmark speech failed to resolve the matter politically. Wright continued his sharp-edged remarks six weeks later in Washington, D.C., even suggesting that Obama actually embraced his views more than he publicly let on. The next day Obama was forced to denounce  and, yes, effectively disown  his former pastor in a press conference.